Contrast-enhanced computed tomography for the diagnosis of fatty liver: prospective study with same-day biopsy used as the reference standard

Purpose: The study purpose was to prospectively determine the accuracy of contrast-enhanced CT in diagnosing fatty liver using same-day biopsy as the reference standard. Materials and methods: One hundred seventy-nine potential living liver donors underwent unenhanced and portal-phase contrast-enhanced hepatic CT and subsequent liver biopsy on the same day. Attenuation difference between the liver and the spleen on unenhanced ( (pre) L-S) and contrast-enhanced ( (post) L-S) images and blood-subtracted hepatic attenuation on contrast-enhanced images ( (post) L-B), calculated by [L - 0.3 x (0.75 x P + 0.25 x A)]/0.7 where L, P and A represent the attenuation of the liver, main portal vein and abdominal aorta, respectively, were obtained. The accuracy of these indices in diagnosing fatty liver according to various threshold levels, 5%-30% histological steatosis in increments of 5%, was compared using ROC analysis. Results: The area under the ROC curve for (pre) L-S, (post) L-S and (post) L-B was 0.663-0.918, 0.712-0.847 and 0.821-0.923, respectively, depending on the threshold levels of hepatic steatosis. The accuracy of (pre) L-S and (post) L-S did not differ (P a parts per thousand yenaEuro parts per thousand 0.054), despite a trend towards a lower accuracy with (post) L-S. (post) L-B yielded higher accuracy than (pre) L-S at threshold levels of 5% and 10% (P a parts per thousand currency signaEuro parts per thousand 0.002) and similar accuracy to (pre) L-S at the other threshold levels (P a parts per thousand yenaEuro parts per thousand 0.144). Conclusion: Portal-phase contrast-enhanced CT has a similar, or even greater, accuracy than unenhanced CT in diagnosing fatty liver.